ASTM D4470-97(2004)
(Test Method)Standard Test Method for Static Electrification
Standard Test Method for Static Electrification
SIGNIFICANCE AND USE
Whenever two dissimilar materials are contacted and separated, excess electrostatic charge (triboelectric charge) will be found on these materials if at least one of the materials is a good insulator. This excess charge gives rise to electric fields which can exert forces on other objects. If these fields exceed the breakdown strength of the surrounding gas, a disruptive discharge (spark) may occur. The heat from this discharge may ignite explosive atmospheres, the light may fog photosensitized materials, and the current flowing in a static discharge may cause catastrophic failure of solid state devices. Electric forces may be used beneficially, as in electrostatic copying, spray painting and beneficiation of ores. They may be detrimental as when they attract dirt to a surface or when they cause sheets to stick together. Since most plastic materials in use today have very good insulating qualities, it is difficult to avoid generation of static electricity. Since it depends on many parameters, it is difficult to generate static electricity reliably and reproducibly.
SCOPE
1.1 This test method covers the generation of electrostatic charge, the measurement of this charge and its associated electric field, and the test conditions which must be controlled in order to obtain reproducible results. This test method is applicable to both solids and liquids. This test method is not applicable to gases, since a transfer of a gas with no solid impurities in it does not generate an electrostatic charge. This test method also does not cover the beneficial uses of static electrification, its associated problems or hazards, or the elimination or reduction of unwanted electrostatic charge.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation: D4470 – 97 (Reapproved 2004)
Standard Test Method for
1
Static Electrification
This standard is issued under the fixed designation D4470; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 conductingmaterial(conductor),n—amaterialwithin
which an electric current is produced by application of a
1.1 This test method covers the generation of electrostatic
voltage between points on or within the material.
charge, the measurement of this charge and its associated
3.1.1.1 Discussion—Theterm“conductingmaterial”isusu-
electric field, and the test conditions which must be controlled
ally applied only to those materials in which a relatively small
in order to obtain reproducible results. This test method is
potentialdifferenceresultsinarelativelylargecurrentsinceall
applicable to both solids and liquids. This test method is not
materials appear to permit some conduction current. Metals
applicable to gases, since a transfer of a gas with no solid
and strong electrolytes are examples of conducting materials.
impurities in it does not generate an electrostatic charge. This
3.1.2 electric field strength, n—the magnitude of the vector
test method also does not cover the beneficial uses of static
force on a point charge of unit value and positive polarity.
electrification, its associated problems or hazards, or the
2
3.1.3 excess electrostatic charge, n—the algebraic sum of
elimination or reduction of unwanted electrostatic charge.
all positive and negative electric charges on the surface of, or
1.2 The values stated in SI units are to be regarded as the
in, a specific volume.
standard.
3.1.4 insulatingmaterial(insulator),n—amaterialinwhich
1.3 This standard does not purport to address all of the
a voltage applied between two points on or within the material
safety concerns, if any, associated with its use. It is the
produces a small and sometimes negligible current.
responsibility of the user of this standard to establish appro-
3.1.5 resistivity, surface—the surface resistance multiplied
priate safety and health practices and determine the applica-
by that ratio of specimen surface dimensions (width of elec-
bility of regulatory limitations prior to use.
trodes defining the current path divided by the distance
2. Referenced Documents between electrodes) which transforms the measured resistance
3
to that obtained if the electrodes formed the opposite sides of
2.1 ASTM Standards:
a square.
D618 Practice for Conditioning Plastics for Testing
3.1.5.1 Discussion—Surface resistivity is expressed in
D5032 Practice for Maintaining Constant Relative Humid-
ohms.Itispopularlyexpressedalsoasohms/square(thesizeof
ity by Means of Aqueous Glycerin Solutions
thesquareisimmaterial).Surfaceresistivityisthereciprocalof
E104 Practice for Maintaining Constant Relative Humidity
surface conductivity.
by Means of Aqueous Solutions
3.2 Definitions of Terms Specific to This Standard:
3. Terminology
3.2.1 apparentcontactarea,n—theareaofcontactbetween
two flat bodies.
3.1 Definitions:
3.2.1.1 Discussion—It is the area one would calculate by
measuringthelengthandwidthoftherectangularmacroscopic
1
This test method is under the jurisdiction of ASTM Committee D09 on
contact region.
Electrical and Electronic Insulating Materials and is the direct responsibility of
3.2.2 dissipative material, n—a material with a volume
Subcommittee D09.12 on Electrical Tests.
12
4
Current edition approved March 1, 2004. Published March 2004. Originally
resistivitygreaterthan10 ohm-cmandlessthan10 ohm-cm,
approved in 1985. Last previous edition approved in 1997 as D4470–97. DOI:
a resistivity range between conductive and insulating material
10.1520/D4470-97R04.
2
as defined in this test method.
Vosteen, R. E., and Bartnikas, R., Chapter 5, “Electrostatic Charge Measure-
ments,” Engineering Dielectrics, Vol. IIB, Electrical Properties of Solid Insulating 3.2.3 real contact area, n—the regions of contact between
Materials, Measurement Techniques , R. Bartnikas, Editor, ASTM STP 926,ASTM,
two bodies through which mechanical actions or reactions are
Philadelphia, 1987.
transferred.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
4
the ASTM website. Annual Book of ASTM Standards, Vol 11.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.